Voting Choices
1. **Problem Statement:**
A voter can choose among candidates for three positions:
- President: Ahmed or Radwa (2 choices)
- Vice-President: Karam, Menna, or Eman (3 choices)
- Secretary: Fayez, Gana, or Nadia (3 choices)
We need to analyze the number of ways to complete the ballot under different conditions.
2. **Tree Diagram Explanation:**
The tree has three levels:
- Level 1 (President): 2 branches (Ahmed, Radwa)
- Level 2 (Vice-President): from each President choice, 3 branches (Karam, Menna, Eman)
- Level 3 (Secretary): from each Vice-President choice, 3 branches (Fayez, Gana, Nadia)
Total pathways = $2 \times 3 \times 3 = 18$
3. **Part a: Draw a tree diagram**
The tree diagram visually represents all possible voting combinations as described above.
4. **Part b: Number of ways if voter may abstain in some or all elections**
If abstaining (not voting) is allowed for each position, add 1 choice ("no vote") per position:
- President: $2 + 1 = 3$
- Vice-President: $3 + 1 = 4$
- Secretary: $3 + 1 = 4$
Total ways = $3 \times 4 \times 4 = 48$
5. **Part c: Number of ways if voter chooses Radwa for President**
Fix President choice to Radwa (1 way), Vice-President and Secretary remain the same:
- Vice-President: 3 choices
- Secretary: 3 choices
Total ways = $1 \times 3 \times 3 = 9$
6. **Part d: Number of ways if voter does not vote for Eman for Vice-President**
Exclude Eman from Vice-President choices:
- President: 2 choices
- Vice-President: $3 - 1 = 2$ choices (Karam, Menna)
- Secretary: 3 choices
Total ways = $2 \times 2 \times 3 = 12$